Hazardous waste is by-products of society that can pose a substantial hazard to human health or the environment when improperly managed. Hazardous waste can be determined by ignitability; corrosivity; reactivity; halogenated hydrocarbons concentration; Polycyclic Aromatic Hydrocarbon concentration; polychlorinated Dibenzo p‐dioxins and dibenzofurans concentrations; and Polychlorinated Biphenyls concentration.
Major Sources of Hazardous Waste in Nigeria
Crude Oil Spillage
The petroleum and petrochemical industries are the major sources of environmental hazard materials in the country. From 1976 – 1996, there was a total of 4,835 spills in Nigeria resulting in a spill volume of 2.3 million barrels of crude oil. From 1976 – 1991, 2,796 spills of about 2.1 million barrels of the oil spill was reported. This accounts for about 40% of total oil spills of the Royal Dutch/Shell company.
It is on record that Nigeria is the highest gas flarer in the world. It has been estimated that the total emission of carbon dioxide (CO2) from gas flaring in Nigeria amounts to about 35 million tonnes/year. The average rate of gas flaring in Nigeria over the period 1970 – 1979 stood at 97 %, while for the period 1980 – 1989, this stood at about 72 %, falling marginally to an average of 72% during 1990 – 2000.
Waste electrical and electronic equipment (WEEE) contains hazardous materials such as lead, mercury, beryllium, cadmium, and brominated flame-retardants that pose both human and environmental health threat. WEEE generated in Nigeria sums up to 1.1 million tonnes for 2010, which is around 7 kg per capita. This includes at least 100,000 tonnes of WEEE that entered the country illegally in 2010.
Crude mining activates in states like Zamfara and Plateau expose farmlands and rivers to toxic chemicals such as lead, sulfur, arsenic, mercury and cyanide which are a threat to humans and the environment.
Household Hazardous Waste
Most household wastes include among others: household cleaners, materials for home maintenance, garden products, and automotive products, the used contents or leftovers of these products, are either poisonous, toxic, flammable, caustic, corrosive, reactive, explosive, radioactive or a combination of these characteristics.
Healthcare activities in Nigeria generate significant amounts of hazardous wastes, such as chemotherapeutic agents, radio nucleoside, mercury, anaesthetics gas, corrosive and expired pharmaceuticals. Used needles, blood-stained cotton and expired drugs are categorized as hazardous medical wastes because they can be poisonous or toxic. In a study of 5 big health faculties in Abuja, the average waste generation rate per bed/day was found to be 2.78 kg of solid waste, 26.5 % of the total waste was hazardous.
Problems and Challenges
Medical waste is often mixed with municipal solid waste and disposed of in residential waste landfills or improper treatment facilities. A study showed that 18.3 % of hospital studied incinerated waste in a locally built brick incinerator, 9.1 % bury their waste, 36.3 % burn their waste in open pits, while 36.3 % dispose their waste into municipal dumpsites.
Low operating temperatures (~ 200 °C) of current medical waste incinerators, results in the excess generation of dioxins and furans. Since these facilities (at hospitals) are usually located in very close proximity to communities, the emissions from the incinerators present a serious health risk to the same community which the hospital is meant to be serving.
In Port Harcourt, it was found that hospital wastes were not segregated into colour coded containers for the different waste streams, neither do they keep records of waste generation and disposal. Pharmaceutical waste management in some Nigerian pharmaceutical industries was assessed. It was found that more than 50% of the staff, supposedly in charge of waste, were not trained to effectively manage waste. Those that were trained were either taught just the basics or had their training many years back and so were not aware of current trends in hazardous waste management.
WEEE collection in Nigeria is not organised; there are no collection centres and most times, they are dumped along with other wastes. A lot of WEEE are also stockpiled in offices and homes, though states such as Lagos have started stockpiling of WEEE pending when a recycling facility is built. Currently, treatment/Recycling is carried out by the informal sector with no knowledge of the environmental and health effects of improper WEEE management.
Most local communities in Zamfara state use Mercury Amalgamation Method in extracting gold, a process particularly degrading and creates a morass of hazardous waste. It has been established that monazite, pyrochlore and xenotime, which are obtained as by-products of tin mining in the Jos Plateau, are radioactive. Mysterious deaths have been attributed to a high level of radiations released by monazite-rich sand used for building the houses in which the deceased lived in, in these areas.
The biggest problem is that federal and state governments put in too little effort to enforce environmental laws especially when it involves big multinationals.
Large hazardous wastes have been produced by Agip, a rich multinational company in oil-producing communities in Ogba/Egbema/Ndoni Local Government Areas of Rivers State. It is stated in research findings that the company use inadequate and below standard disposal strategies, a common situation in Nigeria.
Chevron (Nig) Ltd had severally been accused of contravening the Environmental Impact Assessment (EIA) Act by embarking on a drilling project without EIA.
Ogoniland was polluted by the Royal Dutch/Shell company with hazardous waste for 50 years. It took the intervention of the UNEP in 2011 before Nigerian government saw the need for action which was not taken until June 2nd, 2016 when President Buhari officially launched a clean-up.
In the 8th NEC, non-compliance of industries and organisations to set standards and guidelines was noted with dismay. The council noted with concern that some of the environmental problems in the country are attributed to non-compliance with the provisions of environmental laws.